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From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Keith Busch <keith.busch@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <zwisler@kernel.org>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org
Subject: [PATCH] libnvdimm: fix NULL pointer dereference
Date: Tue, 24 Jul 2018 08:40:06 -0500	[thread overview]
Message-ID: <20180724134006.GA2775@embeddedor.com> (raw)

ndd is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after ndd has been properly
null checked at line 554: if (!ndd)

Addresses-Coverity-ID: 1472020 ("Dereference before null check")
Fixes: 42218e643bd2 ("libnvdimm: Use max contiguous area for namespace size")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/nvdimm/dimm_devs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 9e977cb..1dc3125 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -546,7 +546,7 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
 					   struct nd_mapping *nd_mapping)
 {
 	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
-	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus *nvdimm_bus;
 	resource_size_t max = 0;
 	struct resource *res;
 
@@ -554,6 +554,8 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
 	if (!ndd)
 		return 0;
 
+	nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+
 	if (reserve_free_pmem(nvdimm_bus, nd_mapping))
 		return 0;
 	for_each_dpa_resource(ndd, res) {
-- 
2.7.4

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

WARNING: multiple messages have this Message-ID (diff)
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Keith Busch <keith.busch@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <zwisler@kernel.org>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>
Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH] libnvdimm: fix NULL pointer dereference
Date: Tue, 24 Jul 2018 08:40:06 -0500	[thread overview]
Message-ID: <20180724134006.GA2775@embeddedor.com> (raw)

ndd is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after ndd has been properly
null checked at line 554: if (!ndd)

Addresses-Coverity-ID: 1472020 ("Dereference before null check")
Fixes: 42218e643bd2 ("libnvdimm: Use max contiguous area for namespace size")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/nvdimm/dimm_devs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 9e977cb..1dc3125 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -546,7 +546,7 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
 					   struct nd_mapping *nd_mapping)
 {
 	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
-	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus *nvdimm_bus;
 	resource_size_t max = 0;
 	struct resource *res;
 
@@ -554,6 +554,8 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
 	if (!ndd)
 		return 0;
 
+	nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+
 	if (reserve_free_pmem(nvdimm_bus, nd_mapping))
 		return 0;
 	for_each_dpa_resource(ndd, res) {
-- 
2.7.4


             reply	other threads:[~2018-07-24 13:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-24 13:40 Gustavo A. R. Silva [this message]
2018-07-24 13:40 ` [PATCH] libnvdimm: fix NULL pointer dereference Gustavo A. R. Silva
2018-07-24 19:46 ` Keith Busch
2018-07-24 19:46   ` Keith Busch

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